As is known in the art, in a robot of a SCARA type the operating unit of the robot is carried by a shaft, which is mounted on the distal arm of the robot so that it can rotate about its own axis and at the same time is mobile in translation along this axis. The actuation assembly for driving the shaft is contained within the robot arm in question. To facilitate installation of the actuation assembly on the arm, the latter is usually constituted by a base body, fixed on which is the actuation assembly, and by a covering body, which is fixed on the base body and together with the latter comes to constitute the outer housing within which the actuation assembly is enclosed.
In some sectors of use of the above type of robots, for example in the field of the production of foodstuff products or of sanitary articles, it is important to guarantee that the working area of the robot is not contaminated by the robot itself, for example on account of grease, oil, etc., which could be released and dispersed by the robot. On the other hand, in certain applications, the robot may, instead, be exposed to the presence of liquids so that it is necessary to prevent any possible penetration of these liquids within the parts of the robot.
In the art, there have already been produced robots of a SCARA type that are appropriately prearranged so that they can be used in the applications referred to above. These robots have, in particular, the aforesaid distal arm, bearing the operating unit, that is hermetically closed with respect to the external environment and is equipped with bellows associated to the above mobile shaft in order to prevent any passage of air between the shaft and the housing of the arm. Hermetic closing on the one hand protects the electrical and mechanical members arranged within the arm and on the other hand prevents any material that might contaminate the working area from coming out of the robot.